Most known escapements comply with the very general description that has just been given.
This is the case of the Swiss lever escapement wherein the balance launching and wheel set locking means are united in a pallet assembly including two pallet stones, each of which fulfil both the function of launching the balance and locking the escape wheel set. In this system, the balance receives two impulses by oscillation, not directly, but via the lever assembly inserted between the escape wheel set and the balance.
This is also the case of the coaxial escapement and the single wheel escapement disclosed in the work entitled “La Montre: principes et méthodes de fabrication”, by George Daniels, Scriptar Editions S.A., La Conversion, Lausanne 1993, pages 240 to 248. In these escapements, the means for locking the escape wheel set are formed by a pallet assembly including two locking pallet stones. The balance launching means are formed on the one hand by a first impulse pallet stone, arranged on the pallet assembly and on the other hand by a second impulse pallet stone arranged on the balance roller. In these systems, the balance also receives two impulses per oscillation, one indirect via the first pallet stone arranged on the pallet assembly and the other direction via the second pallet stone arranged on the roller.